The present invention relates to a personal computer system including a portable modular personal computer (hereinafter referred to as a xe2x80x9cmodular PCxe2x80x9d). More specifically, the present invention relates to a modular PC, which is designed such that a side face of a housing is cooled by a cooling air flow from outside instead of providing cooling means such as a cooling fan inside the modular PC in order to enhance portability thereof, and that the inside and outside of the modular PC are cooled simultaneously by drawing out air utilizing negative pressure generated by a diffuser designed to generate differential pressure. The present invention also relates to a connection device for effectuating efficient cooling of the modular PC by connecting to the modular PC, a method of cooling the modular PC, and a personal computer system including the modular PC and the connection device.
Portable personal computer terminals such as pagers or personal digital assistants are widely used in recent years. More recently, in order to enhance usability of the above-mentioned portable personal computer terminals, there is proposed a modular PC using elements such as a central processing unit (CPU), hard disk drive and memory while separating a display unit. The modular PC is constituted as detachable from a portable connection device including displaying means such as a liquid crystal display device, or from a desktop connection device for effectuating display on a desktop display device (such a desktop connection device is hereinafter referred to as a docking station in this specification). Such a system is connected to the portable connection device or to the desktop connection device disposed on the top of a desk for performing high-level processing, as necessary, to enhance user-friendliness.
As described above, a modular PC includes elements such as a CPU, memory and small hard disk drive therein. Some important issues on the modular PC include, achievement in down-sizing to enhance portability, energy designs therefor, and efficient measures against heat generated from a heat source such as the CPU considering the life of internal elements accommodated in a housing.
As disclosed in Japanese Unexamined Patent Publication No. 2000-165077, it has been proposed to cool the inside of a personal computer using an external cooling device to generate an air flow within the personal computer by blowing air into the inside of the personal computer and drawing out the air from the inside with cooling means such as a cooling fan.
However, according to the cooling method disclosed in Japanese Unexamined Patent Publication No. 2000-165077, it is necessary to flow a large amount of air for cooling the entire computer. Accordingly, when a user works on the personal computer by disposing a docking station on the top of a desk for connecting the down-sized modular PC, noises attributable to the cooling fan are increased when the user enhances the capability of the cooling fan in order to supply a larger air flow to the modular PC. Therefore, there is inconvenience that a countermeasure against the noises is required.
Further, Japanese Unexamined Patent Publication No. 2000-227823 discloses a method of cooling the inside of a personal computer by using an air flow generated with a cooling fan disposed inside the personal computer, and also using the Bernoulli theorem. FIG. 16 illustrates the method of cooling the inside of a personal computer disclosed in Japanese Unexamined Patent Publication No. 2000-227823.
As shown in FIG. 16 of the accompanying drawings, air inside a personal computer 80 is discharged to the outside of the personal computer 80 in a direction indicated by an arrow A by a cooling fan 82 disposed therein. However, in a lower region inside the personal computer 80 partitioned by a printed circuit board 84, the cooling fan 84 cannot generate or supply a sufficient air flow, whereby heat tends to remain in the region. Therefore, according to the method disclosed in Japanese Unexamined Patent Publication No. 2000-227823 as illustrated in FIG. 16, an opening 86 is provided in the vicinity of the cooling fan 82, and a diffuser 88 is disposed so as to cover the opening 86. With such a configuration, static pressure is reduced in the vicinity of the opening 86 according to the Bernoulli theorem. Therefore, even in the region where the airflow caused by the cooling fan 82 cannot be supplied sufficiently inside the personal computer 80, the air therein is drawn out in a direction indicated by an arrow B, and cooling efficiency is thereby improved.
Although the cooling method disclosed in Japanese Unexamined Patent Publication No. 2000-227823 can cool the region where the cooling fan cannot generate the air flow efficiently, it is not applicable to a modular PC which requires enhanced portability, long-term drive with low power consumption, and achievement of smaller size and lighter weight. Further, simply disposing the external cooling device as disclosed in Japanese Unexamined Patent Publication No. 2000-165077, it is inevitable to increase a capacity of the cooling fan unnecessarily larger as described above. Accordingly, when the modular PC is used with it being connected to the desktop connection device placed on the top of a desk, a separate measure should be taken to reduce loud noise generated by the cooling fan, which causes inconvenience that portability and compactness of the modular PC are lowered.
In view of the above, it is an object of the present invention to provide a modular PC, a connection device usable in combination with the modular PC, a method of cooling the modular PC, and a personal computer system using the cooling method, in which the personal computer system is composed of separate modules such as the modular PC and a desktop connection device, and the inside of the modular PC is efficiently cooled while maintaining portability and compactness of each module.
The present invention cools a modular PC by cooling an outside wall thereof, and also creates negative pressure inside the modular PC by means of cooling air flowing along the outside wall so that the cooling air flow is drawn in. The present invention is based on the finding that cooling efficiency can be considerably improved if the air flow thus drawn in is usable for cooling a heat source such as a CPU. Thus, the present invention performs cooling by first creating the air flow along the outside wall of the modular PC, so as to enhance the cooling efficiency of the inside of the modular PC by use of cooling means such as a cooling fan provided, for example, in a desktop connection device placed on the top of a desk.
The modular PC is provided with inlet and outlet openings for the cooling air flow for cooling the inside of the modular PC. In the present invention, a diffuser functioning as differential pressure generating means is formed, which extends near the outlet opening for the cooling air flow and across the direction of the air flow flowing along the outside wall. The diffuser can be disposed either on the modular PC side or on a docking station side.
As the air flow moves along an outside wall surface of the modular PC and thereby flows through the diffuser, static pressure in the vicinity of the diffuser is reduced according to the Bernoulli""s theorem. It is possible to draw out the air flow from the inside of the modular PC by positioning the outlet opening in a region where the static pressure is reduced. Negative pressure inside the modular PC thus created allows the cooling air flow to be introduced into the modular PC through the inlet opening. The air flow thus created passes through air passages, which are formed inside the modular PC so as to overlap the CPU, enabling the internal cooling of the modular PC.
Specifically, the present invention provides a personal computer system including a portable module, which comprises a modular personal computer including at least a storage device and a central processing unit inside a housing, used by connecting to a connection device which is separately constituted, and provided with an inlet opening and an outlet opening for a cooling air flow which are disposed on the same side portion of the housing with a space therebetween so as to sandwich the central processing unit, the connection device constituted by including cooling means for cooling the side portion of the modular personal computer, and differential pressure generating means for reducing static pressure near the outlet opening in relation to relative disposition between the modular personal computer and the connection device, wherein the cooling air flow is introduced into the modular personal computer from the inlet opening by reducing the static pressure near the outlet opening to thereby draw out air inside the modular personal computer so as to create negative pressure inside the modular personal computer.
In the personal computer system of the present invention, it is preferred that the static pressure at the outlet opening is reduced by increasing a flow rate of the airflow flowing near the outlet opening by use of the differential pressure generating means. In the personal computer system of the present invention, it is preferred that the differential pressure generating means is constituted as a diffuser disposed close to the outlet opening and on an upstream side in a direction of the air flow flowing near the outlet opening. In the personal computer system of the present invention, the diffuser may be located on the connection device or a side face of the housing, and the connection device may be disposed at least on the top of a desk.
The present invention also provides a modular personal computer including at least a storage device and a central processing unit inside a housing, and used by connecting to a connection device which is separately constituted, which comprises an inlet opening and an outlet opening for a cooling air flow which are disposed on a side portion of the housing facing the connection device while sandwiching the central processing unit, and an air passage extended between the inlet opening and the outlet opening, wherein the cooling air flow is introduced into the modular personal computer from the inlet opening by reducing static pressure near the outlet opening and drawing out air inside the modular personal computer by use of differential pressure generating means for reducing the static pressure near the outlet opening and to thereby create negative pressure inside the modular personal computer.
In the modular personal computer of the present invention, the differential pressure generating means may be constituted as means for increasing a flow rate of the air flow flowing near the outlet opening. In the modular personal computer of the present invention, it is preferred that the differential pressure generating means is disposed close to the outlet opening and on an upstream side in a direction of the air flow flowing near the outlet opening. In the modular personal computer of the present invention, it is preferred that the differential pressure generating means is located on the housing. In the modular personal computer of the present invention, it is preferred that a thermodiffusive member is thermally connected to the central processing unit, and that the thermodiffusive member is extended beyond the inlet opening and the outlet opening and across the cooling air flow. It is also preferred that a cooling air passage is formed between the thermodiffusive member and a side portion of the housing on which each of the openings is formed.
The present invention further provides a connection device to be connected to a modular personal computer including at least a storage device and a central processing unit inside a housing, used by connecting to the connection device which is separately constituted, and provided with an inlet opening and an outlet opening for a cooling air flow which are disposed on a side portion of the housing with a space therebetween so as to sandwich the central processing unit, which comprises means for generating an air flow along the side portion of the modular personal computer when the connection device is connected to the modular personal computer, and differential pressure generating means for reducing static pressure of the air flow near the outlet opening in relation to relative disposition between the modular personal computer and the connection device to thereby create negative pressure inside the modular personal computer through the outlet opening.
In the connection device of the present invention, it is preferred that the differential pressure generating means introduces the cooling air flow from the inlet opening by reducing the static pressure near the outlet opening to thereby draw out air inside the modular personal computer so as to create negative pressure inside the modular personal computer. In the connection device of the present invention, the differential pressure generating means may be constituted as means for increasing a flow rate of the air flow flowing near the outlet opening. In the connection device of the present invention, it is preferred that the differential pressure generating means is disposed close to the outlet opening and on an upstream side in a direction of the air flow flowing near the outlet opening. In the connection device of the present invention, it is preferred that the differential pressure generating means is located on the connection device and that the connection device is disposed at least on the top of a desk.
The present invention further provides a method of cooling a modular personal computer, comprising the steps of providing a modular personal computer including at least a storage device and a central processing unit inside a housing, used by connecting to a connection device which is separately constituted, and provided with an inlet opening and an outlet opening for a cooling air flow which are disposed on the same side portion of the housing with a space therebetween so as to sandwich the central processing unit, connecting the side portion of the modular personal computer closely to the connection device including cooling means, generating a cooling air flow in the modular personal computer from the cooling means, reducing static pressure near the outlet opening by relative displacement between the modular personal computer and the connection device, and introducing the cooling air flow into the modular personal computer from the inlet opening by reducing the static pressure near the outlet opening to thereby draw out air inside the modular personal computer so as to create negative pressure inside the modular personal computer.
In the cooling method of the present invention, the reducing step may include the step of increasing a flow rate of the air flow flowing near the outlet opening by use of differential pressure generating means. In the cooling method of the present invention, the reducing step may include the step of increasing a flow rate of the air flow flowing near the outlet opening by use of a diffuser disposed closed to the outlet opening and on an upstream side in a direction of the air flow flowing near the outlet opening. In the cooling method of the present invention, it is preferred that the diffuser is located on the connection device or a side face of the housing, and that the connection device is disposed at least on the top of a desk. In the cooling method of the present invention, it is preferred that a thermodiffusive member is thermally connected to the central processing unit, and that the thermodiffusive member is extended beyond the inlet opening and the outlet opening and across the cooling air flow. It is also preferred that an air passage is formed between the thermodiffusive member and the side portion of the housing on which each of the openings is formed.